1. Field of the Invention
The present invention relates to a variable valve operating control apparatus for an internal combustion engine having a variable valve timing mechanism and a control method thereof.
2. Description of the Related Art
In Japanese Unexamined Patent Publication 2000-297686, there is disclosed a variable valve timing mechanism which varies a timing of opening and closing an engine valve due to a rotational phase of a camshaft with respect to a crankshaft of an internal combustion engine being varied.
In a control apparatus for the variable valve timing mechanism, a rotational phase is detected on the basis of a interval between a detection signal at a reference rotational position of a crankshaft and a detection signal at a reference rotational position of a camshaft, and the variable valve timing mechanism is feedback-controlled on the basis of the detected result.
When a rotational phase is detected on the basis of the reference rotational positions, a detected value as a rotational phase is updated each constant crank angle.
Therefore, if a period for the updating is made long due to an engine being operated at low rotational speed, a large deviation is generated between a detected value and an actual value during the interval of updating.
Then, there are cases in which an overshoot is brought about due to feedback control being carried out on the basis of a detected value as a rotational phase different from an actual value during the interval of updating.